The calculated distance (air line) between Mykolayiv and Yuzhnoukrayinsk is approximately 70 miles respectively 113 kilometers.
By car or train, the actual journey to Yuzhnoukrayinsk is certainly longer, as only the direct route (as the crow flies) between Mykolayiv and Yuzhnoukrayinsk has been calculated here.
Air line (approximately)
113 kilometers
61 nautical miles